Figure 4.

In vivo MR images and biodistribution of designed contrast agents. (a) MR images of mouse (26 g) pre-(left) and 40 minutes post-(right) injection of 50 μL of 1.2 mM Gd³⁺-CA1.CD2 through the tail vein. The MRI was performed using a spin echo sequence with TE/TR = 15 ms/500 ms using a 3T scanner. The arrows indicate the contrast enhancements at different organ sites. (b) The MRI signal intensity changes at kidney (●), liver (▲), and muscle (◇) as a function of time. The 0 refers to the pre-injection. (c) Tissue distributions 1 hour post-intravenous injection of Gd³⁺-CA1.CD2 (3.0 μmole/kg, solid black), Gd³⁺-DTPA (150 μmole/kg, grey), and GdCl₃ (100 μmole/kg, open). The Gd3+ in tissues was measured by ICP-MS and was calculated and expressed as a percentage of the injected dose.⁵³ The Gd³⁺ retained in the animal carcass (i.e. - the remainder of the whole body after removing indicated organs) is calculated as the mean from 10 randomly-selected sites. Error bars in (a), (b), and (c) are standard deviations of four measurements or four animals (n=4).